Neurophysiology Part 2

Front 1

ipRGCs

Back 1

-intrinsically photosensitive retinal ganglion cells
-small percentage of ganglion cells
-contain melanopsin a photopigment which allows them to respond directly to light
-less sesnsitive to light than rods and cones bc of low pigment density
-response to light is depolarization
-non-image forming vision and participate in pupillary light reflex and circadian rhythms

Front 2

What can rod cells do that cones cannot?

Back 2

-detect dim light

Front 3

Axons from optic tract to superior colliculus

Back 3

-participates in reflex orienting the head in response to visual or other stimuli
-these projections might explain phenomenon of "blind sight"

Front 4

axons from optic tract to hypothalamus

Back 4

-projections to suprachiasmatic nucleus of hypothalamus
-probably act to train biological clock

Front 5

axons from optic tract to pretectal area

Back 5

-at junction of midbrain and diencephalon
-pretectal neurons project to edinger-westphal nucleus
-participate in pupillary light reflex

Front 6

Where do the frontal eye fields project to?

Back 6

-superior colliculus
-caudate nucleus
-horizontal and vertical gaze centers

Front 7

Where are the frontal eye fields located?

Back 7

Brodmann's area 8 in frontal lobe

Front 8

Where do the frontal eye fields receive input from?

Back 8

-from primary and association areas of visual cortex, supplementary eye feilds, dorsolateral prefrontal cortex, and auditory and somatosensory association areas

Front 9

retinal disparity

Back 9

-target not on fovea of both eyes

Front 10

retinal blur

Back 10

target out of focus

Front 11

What area of the brain are jacksonian seizures associated with?

Back 11

primary motor cortex

Front 12

What are electrical stimulations of the premotor cortex associated with?

Back 12

-more complex movements than primary motor cortex
-coordinated contractions over more than one joint
-orientation of body for upcoming movement and initiation of movement especially movements related to external stimuli

Front 13

What area of the brain is associated with internally generated movements often involving both sides of the body?

Back 13

-supplementary motor area

Front 14

Electrical stimulation of the supplementary motor area will produce what?

Back 14

-vocalization or complex postural movements
-movements involving bilateral muscle groups

Front 15

How are the frontal eye fields involved in coordinating eye movements?

Back 15

-triggers saccadic movement
-participates in coordinating smooth pursuit movements

Front 16

What tract has some fibers ending on dorsal gray matter and ventral and intermediate gray?

Back 16

corticospinal tract

Front 17

3 sources of input for the reticulospinal tract?

Back 17

1)basal ganglia
2)motor cortex
3)somatosensory cortex

Front 18

Where does the reticulospinal tract originate in?

Back 18

pontine and medullary reticular formation

Front 19

What tract is responsible for complex reflexes (yawning, suckling orienting)

Back 19

reticulospinal tract

Front 20

indirect ascending pathway

Back 20

the way the basal ganglia exerts motor control.
-modifies which descending cerebral output to motoneurons

Front 21

What part of the basal ganglia controls saccadic eye movements?

Back 21

-caudate

Front 22

Parkinsons is produced by the loss of which tract?

Back 22

-nigrostriatal dopaminergic tract

Front 23

describe problems in the basal ganglia associated with parkinson's disease

Back 23

-loss of nigrostriatal dopaminergic tract reduces inhibitory output of the striatal neurons on GPi resulting in greater inibition of thalamus
-less inhibitory sriatal output to GPe producing a disinhibition of the subthalamic nucleus and thereby inhibition of thalamic output

Front 24

levodopa

Back 24

-treatment for parkinsons
-precursor for DA synthesis
-passes blood brain barrier
-probably taken up by remaining dopaminergic neurons

Front 25

anticholinergics to treat parkinsons

Back 25

-used to be most effective
-with loss of nigrostriatal neurons cholinergic interneuons in striatum become more actitive

Front 26

pallidotomy

Back 26

-treatment for parkinsons
-lesion of GPi to decrease output

Front 27

Describe huntington's disease

Back 27

-loss of striatal GABA-ergic neurons which project to GPe but later there is also a loss in cholinergic interneurons from the stiatum
-loss of GABA-ergic = release of GPe from inhibitory influence
-GPe inhibits output of subthalamus nucleus resulting in reduced stimulation of GPi which causes reduction in thalamic inhibition by GPi and increase in cortical output

Front 28

what secretes endolymph?

Back 28

stria vascularis

Front 29

Scala vestibuli

Back 29

-chamber which oval window transmits vibrations
-contains perilymph
-separated from scala media by vesitbular membrane (reissner's membrane)

Front 30

Scala media

Back 30

-contains sense organ for earing (organ of corti)
-contains endolymph
-basilar membrane supports organ of corti and separates scala media from scala tympani

Front 31

Scala tympani

Back 31

-continuous with the scala vestibuli via the heliotrema
-contains perilymph
-contains the round window

Front 32

Which has a high spatial resolution M or P?

Back 32

P cells

Front 33

What reflex is involved in matching target and eye velocity and keep object of interest on fovea?

Back 33

smooth pursuit

Front 34

Does saccadic eye movement require a target?

Back 34

no

Front 35

Saccades

Back 35

-can be voluntary or reflex
-very accurate
-vision is lost during saccade (velocity is about 700 degrees/sec. Identical to fast phase of nystagmus)
-involvement of superior colliculus

Front 36

Describe the involvement of the superior colliculus in saccades?

Back 36

-sensory and motor maps
-maps are linked: a certain location in the s. colliculus = a point in space
-projects to gaze centers
-cerebellum controls gain

Front 37

Function of interposed?

Back 37

-correction of actual movement

Front 38

basic functions of the cerebellum

Back 38

- equilibrium and control of eye movements (control the gain of saccades)
-control of rapid, coordinated muscle movement
-execute sequential movements
-compare actual and intended movements and correction
-posture
-motor learning

Front 39

What happens if you damage your olive or flocculonodule node?

Back 39

-cannot make adjustments of motor movements

Front 40

Describe receptor potentials

Back 40

-graded response- amplitude of receptor potential increased with increasing stimulus intensity over a wide range
-decremental conduction

Front 41

generator potential

Back 41

-a specific type of receptor potential involving the depolarization of primary sensory endings produced by a stimulus. Leads to APs in the primary afferent fiber if depolarizations are large enough.

Front 42

Knee jerk reflex

Back 42

-AP in Ia produce monosynaptic excitation of alpha-motorneurons
-reciprocal innervation
-y-mototneurons maintain tension of intrafusal fibers and sensitivity of extrafusal
-co-activation of alpha and gamma motoneurons

Front 43

inverse stretch reflex

Back 43

-Golgi tendon organ receptor
-reports MUSCLE TENSION
-group Ib fibers inbibit A(alpha) and excite antagonistic muscle

Front 44

Does opiate induced analgesia has a direct actions on ______

Back 44

CNS (not on peripheral receptors)